1. Field of Invention
Generally speaking this invention relates to an improved rotary lawn mower blade having cutting edges which will retain their sharpness longer than those of blades commonly in use at this time. More specifically it relates to a rotary lawn mower blade comprised of a horizontally rotatable metal cutter bar of lesser hardness having a plurality of relatively small cutter segments of greater hardness fusibly bonded along the leading edges of each end of the cutter bar.
2. Description of Prior Art
Numerous attempts have been made to provide a rotary lawn mower blade that has cutting edges which resist abrasion from sand and dirt particles normally encountered during mowing operations. Nonetheless the most commonly used blade of today does not have cutting surfaces that are especially wear resistant. State of the art blades are one piece steel blades which must be sharpened repeatedly during a mowing season or used dull. One difficulty with using hardened cutter elements is that those having sufficient hardness to resist abrasive wear are relatively brittle and thus subject to being broken or nicked as a result of an accidental impact with a stone or other hard object on a lawn. The problem is made even more complicated by the fact that the cutting surfaces are long and narrow. One solution proposed by the prior art to overcome the problem of brittleness was a composite blade constructed with a hardened layer of material sandwiched between two outer layers of more malleable material. Apparently it was too costly to produce or failed to work according to expectations.